A person wishing to partly or fully refuel a fuel tank for an internal combustion engine, or any other fuel consuming device, at a point remote from a fixed base fuel pumping station, may use a rudimentary portable fuel container comprising a small tank fitted with a pouring spout which typically is somewhat flexible in its structure. Particularly when the portable container is full or near full, it is difficult to transfer the fuel from that container to the container to be refilled without spilling some of the fuel. Of course, it will be recognized that such spilled fuel represents a serious safety hazard.
In those cases where the fuel tank to be refilled is integral with the engine or device using that fuel, such as is the case with lawn mowers, small outboard engines for marine use, and the like, the hazard may be even greater because the tank and its surroundings are frequently very hot when the engine or device has just been used and has run the fuel out of its typically small fuel tank. Thus, a source of ignition for fuel vapors and liquid fuel is ready at hand.
Of course, aside from the safety considerations set forth, supra, it is very undesirable for a person handling such portable fuel units to have fuel, especially gasoline, spill on his or her person or clothing because of the obnoxious and long lasting odor.
Funnels have been used to aid in directing fuel from such portable containers into the tank to be filled. That practice further complicates the operator's attempts to monitor fuel flow to prevent overfilling. Generally, by the time fuel rises in the filled tank to the level of the funnel spout, it is too late to remove the funnel from the tank because of the volume of fuel remaining in the funnel at that time. As a result, spillage occurs nearly every time.